Related topics: light

LED's efficiency exceeds 100%

(PhysOrg.com) -- For the first time, researchers have demonstrated that an LED can emit more optical power than the electrical power it consumes. Although scientifically intriguing, the results won’t immediately result ...

Student's flashlight works by body heat, not batteries

(Phys.org) —Ann Makosinski from Victoria, British Columbia, has an LED flashlight powered by body heat. This inventor has a flashlight that glows when she holds it. The story gets more interesting, though. She is 15 years ...

Physicists score double hit in LED research

In two breakthroughs in the realm of photonics, City College of New York graduate researchers are reporting the successful demonstration of an LED (light-emitting diode) based on half-light half-matter quasiparticles in atomically ...

Flexible LEDs for implanting under the skin

(PhysOrg.com) -- Researchers in the US, China, Korea and Singapore have collaborated to develop flexible ultra-thin sheets of inorganic light emitting diodes (LEDs) and photodetectors for implantation under the skin for medical ...

Perovskite LEDs, a thousand times brighter than OLEDs

Light-emitting diodes (LEDs) have revolutionized modern lighting and sensing technology. From applications in our homes to industry, LEDs are used for all lighting applications, from indoor lighting over TV screens to biomedicine. ...

page 1 from 31

Light-emitting diode

A light-emitting diode (LED) (pronounced /ˌɛliːˈdiː/, or just /lɛd/), is an electronic light source. The LED was first invented in Russia in the 1920s, and introduced in America as a practical electronic component in 1962. Oleg Vladimirovich Losev was a radio technician who noticed that diodes used in radio receivers emitted light when current was passed through them. In 1927, he published details in a Russian journal of the first ever LED.

All early devices emitted low-intensity red light, but modern LEDs are available across the visible, ultraviolet and infra red wavelengths, with very high brightness.

LEDs are based on the semiconductor diode. When the diode is forward biased (switched on), electrons are able to recombine with holes and energy is released in the form of light. This effect is called electroluminescence and the color of the light is determined by the energy gap of the semiconductor. The LED is usually small in area (less than 1 mm2) with integrated optical components to shape its radiation pattern and assist in reflection.

LEDs present many advantages over traditional light sources including lower energy consumption, longer lifetime, improved robustness, smaller size and faster switching. However, they are relatively expensive and require more precise current and heat management than traditional light sources.

Applications of LEDs are diverse. They are used as low-energy indicators but also for replacements for traditional light sources in general lighting and automotive lighting. The compact size of LEDs has allowed new text and video displays and sensors to be developed, while their high switching rates are useful in communications technology.

This text uses material from Wikipedia, licensed under CC BY-SA